GameStop is $50 store credit, $40 for cash on XBOX system trade-ins. EB is owned by GameStop now and would most likely offer the same prices.
As for the games, it depends on the game.
But we are doing a number of trade-in deals.
If you trade towards a pre-order of an upcoming game, you get an extra 10%. That's a deal that we always offer.
If you trade in towards a reservation of Godfather, you get 20%. Of course, that deal ends tomorrow since Godfather comes out the next day.
If you trade in towards the purchase of XBOX 360 games or accessories, you get 20%. I believe that deal ends Tuesday as well.
And finally, if you have a Game Informer card, you can get 10% on all trade-ins.